Branches are organs of complexly interrelated dimensions; despite the relative flexibility of plant growth, high correlations connect most external branch characteristics. Complex interrelations also connect internal characteristics–mean and total cross—section area of branch segments of a given age, number, length, and weight of segments, and wood radial increment and productions–, different patterns of taper along the length of branches appear in different characteristics. Radial wood increment and amount of wood growth decrease from young terminal branchlets down to the base of the branch axis, and amounts of wood production differ widely between vigorous and slow—growing branches. Estimates of branch production are possible from regressions of branch dry weight in relation to branch age. Analyses of actual growth in samples of Rhododendron maximum and Quercus alba branches indicate that such estimates are generally overestimates because growth rates from regressions are excessive when applied to less vigorous branches. The amount of error is not necessarily small but may be acceptable in production research, particularly if some correction for slower growth of some branches is possible.